"use client";

import React, { useState } from "react";
import { Share2 } from "lucide-react";
import { ShareModal } from "./ShareModal";
import { useAnalytics } from "./analytics/useAnalytics";
import * as htmlToImage from "html-to-image";
import QRCode from "qrcode";
import LogoBlack from "../assets/logo/Logo-Black-Transparent.svg";

interface ComponentShareButtonProps {
    targetId: string;
    title?: string;
    shareText?: string;
    className?: string;
}

export const ComponentShareButton: React.FC<ComponentShareButtonProps> = ({
    targetId,
    title = "Mintel Architektur Insights",
    shareText = "Schauen Sie sich diese spannende interaktive Simulation an:",
    className = ""
}) => {
    const [isModalOpen, setIsModalOpen] = useState(false);
    const [generatedImage, setGeneratedImage] = useState<string | undefined>();
    const [isCapturing, setIsCapturing] = useState(false);
    const { trackEvent } = useAnalytics();

    const currentUrl =
        typeof window !== "undefined"
            ? `${window.location.origin}${window.location.pathname}#${targetId}`
            : "";

    const applyWatermark = async (base64Img: string, qrCodeSrc: string): Promise<string> => {
        return new Promise((resolve) => {
            const img = new Image();
            img.onload = () => {
                const canvas = document.createElement("canvas");
                // html-to-image uses pixelRatio: 2, so img.width/img.height are 2x
                canvas.width = img.width;
                canvas.height = img.height;
                const ctx = canvas.getContext("2d");
                if (!ctx) return resolve(base64Img);

                // Draw main image
                ctx.drawImage(img, 0, 0);

                // Watermark styling for 2x resolution
                const padding = 32;
                const wHeight = 110;
                const wWidth = 360;
                const x = canvas.width - wWidth - padding;
                const y = canvas.height - wHeight - padding;

                // Draw pill shape background
                ctx.fillStyle = "rgba(255, 255, 255, 0.95)";
                ctx.shadowColor = "rgba(0, 0, 0, 0.05)";
                ctx.shadowBlur = 10;
                ctx.shadowOffsetY = 4;

                if (ctx.roundRect) {
                    ctx.beginPath();
                    ctx.roundRect(x, y, wWidth, wHeight, 24);
                    ctx.fill();
                } else {
                    ctx.fillRect(x, y, wWidth, wHeight);
                }

                // Draw text and logo
                ctx.shadowColor = "transparent";
                ctx.textBaseline = "middle";

                (async () => {
                    try {
                        const qrImg = new Image();
                        qrImg.src = qrCodeSrc;
                        await new Promise(r => { qrImg.onload = r; qrImg.onerror = r; });

                        const logoSrc = typeof LogoBlack === 'string' ? LogoBlack : (LogoBlack as any).src;
                        const logoImg = new Image();
                        logoImg.src = logoSrc;
                        await new Promise(r => { logoImg.onload = r; logoImg.onerror = r; });

                        if (logoImg.width > 0) {
                            // Calculate logo dimensions
                            const logoHeight = 32;
                            const logoWidth = logoImg.width * (logoHeight / logoImg.height);
                            const logoX = x + 24;
                            const logoY = y + (wHeight - logoHeight) / 2;

                            // Draw Logo
                            ctx.drawImage(logoImg, logoX, logoY, logoWidth, logoHeight);

                            // Draw "Zum Artikel" text right of the logo
                            ctx.font = "600 20px sans-serif";
                            ctx.fillStyle = "#64748b";
                            ctx.textAlign = "left";
                            ctx.fillText("Zum Artikel", logoX + logoWidth + 24, y + wHeight / 2 + 2);
                        } else {
                            // Fallback if logo fails to load for some reason
                            ctx.font = "900 36px sans-serif";
                            ctx.fillStyle = "#0f172a";
                            ctx.textAlign = "left";
                            ctx.fillText("mintel.", x + 24, y + wHeight / 2 + 4);
                        }

                        // Draw solid line separator before QR
                        const qrSize = wHeight - 24; // padding 12*2 inside pill
                        const qrX = x + wWidth - qrSize - 12;
                        const qrY = y + 12;
                        const sepX = qrX - 12;

                        ctx.beginPath();
                        ctx.moveTo(sepX, y + 20);
                        ctx.lineTo(sepX, y + wHeight - 20);
                        ctx.strokeStyle = "#e2e8f0";
                        ctx.lineWidth = 2;
                        ctx.stroke();

                        // Draw QR Code
                        if (qrImg.width > 0) {
                            ctx.drawImage(qrImg, qrX, qrY, qrSize, qrSize);
                        }

                        resolve(canvas.toDataURL("image/png"));
                    } catch (e) {
                        resolve(base64Img); // Error fallback
                    }
                })();
            };
            img.onerror = () => resolve(base64Img); // Error fallback
            img.src = base64Img;
        });
    };

    const handleOpenModal = async () => {
        setIsCapturing(true);
        try {
            const element = document.getElementById(targetId);
            if (element) {
                // Force explicit dimensions to prevent html-to-image from clipping
                const w = element.offsetWidth;
                const h = element.offsetHeight;

                const rawDataUrl = await htmlToImage.toPng(element, {
                    quality: 1,
                    type: 'image/png',
                    pixelRatio: 2,
                    backgroundColor: 'white',
                    skipFonts: true,
                    width: w,
                    height: h,
                    style: {
                        transform: 'none',
                        margin: '0',
                        width: `${w}px`,
                        height: `${h}px`
                    },
                    filter: (node) => {
                        const el = node as HTMLElement;
                        if (el.tagName === 'BUTTON' || el.dataset?.shareButton === 'true' || el.dataset?.shareWrapper === 'true') {
                            return false;
                        }
                        return true;
                    }
                });

                // Generate QR Code
                const qrDataUrl = await QRCode.toDataURL(currentUrl, {
                    width: 120, // slightly larger for sharper scaling
                    margin: 0,
                    color: { dark: '#0f172a', light: '#ffffff' }
                });

                // Add Watermark
                const watermarkedImage = await applyWatermark(rawDataUrl, qrDataUrl);
                setGeneratedImage(watermarkedImage);
            }
        } catch (err) {
            console.error("Failed to capture component:", err);
        } finally {
            setIsCapturing(false);
            setIsModalOpen(true);
            trackEvent("component_share_opened", {
                component_id: targetId,
                component_title: title
            });
        }
    };

    return (
        <div className={`relative ${className}`}>
            <button
                onClick={handleOpenModal}
                disabled={isCapturing}
                data-share-button="true"
                className={`flex items-center gap-2 px-3 py-1.5 rounded-full font-medium text-xs transition-all shadow-sm
                    ${isCapturing
                        ? "bg-slate-100 text-slate-400 cursor-wait border border-slate-200"
                        : "bg-white text-slate-600 hover:text-slate-900 border border-slate-200 hover:border-slate-300 hover:shadow-md"
                    }`}
                title="Diesen Abschnitt als Bild teilen"
            >
                {isCapturing ? (
                    <div className="w-3.5 h-3.5 border-2 border-slate-300 border-t-slate-500 rounded-full animate-spin" />
                ) : (
                    <Share2 size={14} />
                )}
                <span>Teilen</span>
            </button>

            <ShareModal
                isOpen={isModalOpen}
                onClose={() => setIsModalOpen(false)}
                url={currentUrl}
                title={title}
                description={shareText}
                diagramImage={generatedImage}
                qrCodeData={generatedImage} // Let's try sending it to both to be safe depending on ShareModal's internals
            />
        </div>
    );
};